/Engine/Source/Developer/GeometryProcessingInterfaces/Public/GeometryProcessingInterfaces/CombineMeshInstances.h
struct FOutputMesh
int32
InstanceSubsetID
All part instances accumulated into the MeshLODs will have had this InstanceSubsetID in their inputFBaseMeshInstance's.
TArray<UMateri...
MaterialSet
TArray<UE::Geo...
MeshLODs
FKAggregateGeom
SimpleCollisionShapes